N/A 😳 What's wrong with my gun? — Look at this shot string!

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Motorhead said:
As stated by many over and over again .... there is not enough gain in shot count filling above 250 bar weighed against the wear & tear on the systems o-rings & seals to make it worth while.

Yes SERVICE the reg ... don't fill above 250 bar. HST in balanced valved guns generally does little & best run soft as you can go & still open the poppet.
Velocity is controlled with Pressure adjusted at regulator ... NOT the HST setting ;)
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Vetmx said:
This is a little off topic but something I found interesting. And it could also go full circle. It’s about us trying to make tiny guns do what little guns do. Or little guns do what big guns do. My 600mm P2 .25 matches your speed numbers or at least is close enough with my reg set at 108-112b. So now let’s look at my useable shots from 250b down to 115b or so and how my gun sounds and behaves. Sometimes just because our tiny gun will do something doesn’t mean it’s happy doing it. All barrel lengths sitting on whatever platform have a wheelhouse where they operate best and all the numbers look good. Speed, ES and shot count. Might be time to experiment with some lower pellet speeds and friendlier reg settings. A little can go a long way. Sometimes if you want big power and good numbers, you just have to buy the appropriate size gun.
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I'd follow Motorheads info. above, and Vetmx recommending normal pressures and velocity's for a small gun.
The first two shots of a days shooting with a Balance Valve are DRY FIRE! After that it should work reliably, except in extreme cold weather.
Some externally adjustable reg"s can be damaged by lowering the pressure with pressure above the set point.
Assuming the Reg. isn't malfunctioning ------
You could try a Reg. setting around 120 - 125 Bar and adjust the HST to barely open the valve consistently.
The pressure in the barrel can effect the dwell time too. ie slug or pellet weigh and barrel fit plus barrel length do matter.
Have you tried any other slugs or pellets?
Vetmx said - "Sometimes if you want big power and good numbers, you just have to buy the appropriate size gun." So true.....
Just my .02 cents worth.
 
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Here’s something interesting and aligns itself with a comment made in this topic. I was at my camp a month ago with my P2. At that time I had “too much” hammer spring tension by one full turn. I experienced no cold shot issues. At my camp again with my P2 and my hammer set at the +1/4 turn method. Gun was about 32 degrees and was shooting bloopers. Not for one shot, it just wouldn’t pick up speed. I added 1/2 turn to the hammer to get it to be normal. Even though I use quality lubricants within my gun that shouldn’t thicken with temperature changes, I need to remember to run more spring when it isn’t warm out. When I get home I will check my first shot velocity. If it’s on, I’ll just be a 3/4 turn guy instead of a 1/4 turn guy.
 
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Well, I spent a large part of yesterday NOT shooting MY guns — but helping a buddy to learn shot his (very first) gun:
FX DreamTac .22

We had fun.
➧ With HIS gun. 😊 👍🏼


However:
➧ MINE is still acting up.
And thanks, Carl* for your warm welcome to the cold world of HPA guns. Classic! 😆
*"Welcome to the wonderful world of PCP's."



But I did follow up on your suggestions. THANK YOU! 👍🏼


🔶 Let me get this out of the way, first:
You know CAKE, right?
➧ I want to have it.
➧ And: I want to eat it, too. Of course, I do.

➧ I want a short gun.
➧ And: I want lots of power.
➧ And: I want it to shoot quietly.


Yupp, I can see Frank rolling his digital eyes, 🙄
Tom throwing angry HP looks at me, where the HP has 4 slits for massive expansion, 😵
and Erlis is throwing up his virtual hands in desperation. 🤷🏻‍♂️

I will consider your ever so gentle suggestions that I'm a totally unreasonable airgunner and should stop wanting the impossible.
And I will consider finding a compromise. ✅


➠ OK, now, with this basic issue out of the way, let's move to action:



🔶 An HST 3/4 turn in after the velocity dropoff point could prevent slow first shots (rather than a 1/4 turn). Thanks, Frank.
Did that.


🔶 However, when it comes to the "runout on the pin" — I have to claim total ignorance [What are you talking about? 😞] —
and when it comes to get metal parts "within a thousandth" (be that mm or inch) — I have to admit total inability. ➧ The inches I manage in my life have only 8 eighths, not 1000 thousandths.


🔶 Erlis, the red plastic seal seems fine (as far as this beginner can tell, that is).



To be continued....
 
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Cont.:


🔶 Cleaning the reg:
OK, I took it apart again.
And followed the instructions of the video Erlis linked. Thanks! 👍🏼
Well, I used the same grease. I used the same cotton swabs.

➠ But I couldn't use the recommended 5000 grit sandpaper..... 🤦🏻‍♂️
➠ Because I live in a country with 7 presidents in 6 years. All of them ended up in prison. Well, one shot himself while in office.
Countries like that just don't have 5000 grit sandpaper. 😆

● I tried finger nail manicure supply places. But they don't state the grit on their nail boards.
● Is 2000 grit OK? Some paint supply store might have that size.
● Or something else?



🔶 Then, I did another shot string.
Summary:
The REG dropped from 145bar to 131bar in just 5 shots (AIR 260 to 250b). 😱

🔸Then the REG was more stable, but still decreasing pressure as bad as before:
▪AIR: from 250b ➔ to 120b
▪REG: from 131b ➔ to 117b — over a total of 40 shots.

The average MV dropped by 31fps from 938fps to 907fps (55.1FPE to 51.5FPE).




⭐ Well, any more suggestion before I resign myself to write an email to RTI? 😊

Matthias
 
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Vetmx said:
I was out shooting tonight getting my Coyote hold overs at 140, 160 and 200 yards. It’s cold out and gun sat for 24 hours. It was fine. I will see if I can find some pics of the runout on the reg pin. Because of how this reg works, I think it’s important. It may help others that have the tools to address it.
Click to expand...


Thank you!! 😊

And shooting coyotes out to those ranges must be extreme fun! 👍🏼👍🏼
 
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Ok, these are screenshots from a video I made on my phone back when I did it. I’m not a video poster so the first is when I dialed the pin in close to the chuck as close to zero as I could. You have to allow for flaws in the surface or a dust mite turd. Second pic is how much runout that pin had. Spinning in my mini lathe it was like a dogs tail wagging. Last pic was as close as I could get it to zero without going full OCD.

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After you are done dealing with the regulator...

That balanced valve (first shot low) sounds like it should be taken apart, cleaned and polished up, and re-sealed. I need to do this re-clean and polish on one of my b-valves that gets the "first shot low" symptoms when the o-rings and grease take a set after a lot of use. I also switched out the black o-rings to the harder white polyurethane ptfe type and it increased consistency and longevity.
 
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On the other subject of being a power monger. I used to be. When I first got into PCP’s, I pushed all of them. Then two magical things happened. First, they started making guns that produce all the power you need before you’re better off with a powder burner. Second, I woke up. Guys like Qball were posting about how lovely their Dreamtac Compacts were when they had them set where the platform wanted to be. Meanwhile I’m trying to turn mine into a lightweight Impact and punishing it. I knew where the happy spot for all my guns were but I refused to go there. Finally I did and that’s where I’ve remained since. I don’t try to make my M3 compact do what my 600mm does. I don’t try to turn a Prod into a Evol Mini. Life is better. My .30 P2 on this trip has a FX Superior 500mm in it. My reg was 126+or- when I left home. It’s around 130b +or- here. I’m shooting heavy .30 slugs around 860fps. Could I crank the gun up to 160b and try to have a cannon? Yes, but I won’t. If I want to be over 900fps, I’ll slip the LW 600mm back on the gun and never touch the reg. Why? Because I like the harmonics of the shot cycle and my shot count at 130b or less. This reg is untouched by me internally. It was acting a little crazy in the beginning and I’ve adjusted it up and down. But very carefully. I just refilled the gun with a dry fire before taking each picture. Seems good for now.

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Airgun-hobbyist said:
After you are done dealing with the regulator...

That balanced valve (first shot low) sounds like it should be taken apart, cleaned and polished up, and re-sealed. I need to do this re-clean and polish on one of my b-valves that gets the "first shot low" symptoms when the o-rings and grease take a set after a lot of use. I also switched out the black o-rings to the harder white polyurethane ptfe type and it increased consistency and longevity.
Click to expand...
Good to know. I didn’t know they made ptfe orings as small as the one in our P2’s. But I will take some measurements the next time I’m in there.
 
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Vetmx said:
Good to know. I didn’t know they made ptfe orings as small as the one in our P2’s. But I will take some measurements the next time I’m in there.
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The balance valve I do routine maintenance on is in an old original AAA Slayer. Those old style balanced valves get 'stiction syndrome' from the o-rings after a while. Tom's new valves are not doing this, but I haven't changed it out yet.
 
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Vetmx said:
There is a 4mm and a 5.5mm in there. I think the smallest ptfe I’ve ever seen was a 6mm.
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It seems like I saw somewhere, from an o-ring manufacturer, that they would make custom ordered o-rings to size. It's been a while and I can't remember which one. Anyway, is this 4mm the same common size as the 4mm in foster fill probes, or is it a #4? If so, they should easily be made, in both sizes.
 
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There is dude in Poland who makes a valve for the Prophet. He is on ebay:

www.ebay.com

Firing valve pin for RTI Prophet | eBay

Blasting valve needle / pin manufactured by Serwis Wiatrowy and dedicated to the RTI Prophet system. We will respond to you within 72 hours and do our best to help you out!
www.ebay.com

He also makes an adjustable speed dialer for the Prophet hammer spring:

www.ebay.com

RTI Prophet Tension / Energy adjustment of the hammer spring "patencik" MOD.SW 5904119918940 | eBay

Find many great new & used options and get the best deals for RTI Prophet Tension / Energy adjustment of the hammer spring "patencik" MOD.SW at the best online prices at eBay! Free shipping for many products!
www.ebay.com

I ordered one of each. I don't know if this will help anyone without machinery for fix or make.

Can I ask who makes those small digital gauges and are they any good? The gauges on the Prophet are very hard to read to me.
 
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